Healable Supramolecular\nPolyurethane Elastomers Possessing\nPendant Bis-Aromatic Urea Recognition Units for Use in Repairable\nCoatings

This paper describes the synthesis, characterization,\nand supramolecular\nassembly of polyurethane elastomers. Bis-aromatic urea hydrogen-bonding\nmotifs have been used to promote the self-assembly of the materials.\nThe materials described comprise a soft block, namely, polytetramethylene\nether glycol (PTMG), as a telechelic diol and hard crystalline domains\nthat feature a bis-aromatic urea hydrogen bonding motif as a chain\nextender. Two diols were polymerized (one featuring the bis-aromatic\nurea hydrogen bonding motif) with a PTMG diisocyanate prepolymer to\nyield supramolecular polyurethanes with molecular weights <i>ca</i>. 185000 with polydispersities <i>ca</i>. 2.0.\nThe mechanical properties and processing temperatures of the polyurethanes\nwere shown to be tunable by controlling the feed ratio of the supramolecular\nchain extenders. These supramolecular polyurethanes were found to\nbe healable in nature, offering a useful property for use of these\nelastomers in applications such as cable coatings.